On the 24th of October world-wide the astronomers were
confronted with a new phenomenon in the sky. The inconspicuous 16.3mag*bright comet P17/Holmes, discovered 1892 by
Edwin Holmes was by the time only
photographically provable by larger telescopes. On this day the comet increased in its brightness within hours
up to 2,5 mag. Suddenly in the constellation Perseus a third bright
"star" had emerged, which can be discovered despite of the prevailing full moon situation with the naked eyes easily. That means,
the brightness increased by a factor of nearly 500000, while around
the comet nucleus a circular expansion wave made itself recognizable

What
had happened, that this cosmic ice ball in a distance of
2,4 AU (approx. 360 millions km) to the sun, suddenly begins
itself to expand in a perfectly shaped radius? Was it a cosmic collision,
a chemical reaction, or the wall "burst" around a
large cavity within the comet body? May after coming nearer to the planet Mars (map)the green manikindid attack?
So far there is no clear explanation for it !

Photo 1) Comet 17P/
Holmes near the California Nebula on the 3/5/2008. The very
difuse nebula measures now apprx. more than 4,5 times of the
moon diameter. This is equivalent to 2,25 degrees or 135arcmin.

Photo 2) and 3)
1/9/2008: Apprx. 84 arcmin lenght
x 71 arcmin breadth is now the
expansion of 17P/ Holmes by a distance of 2,1 AU (315 Mio. Km)
from the earth. Despite the enormous widness of nearly
7,7 x 6,5 million kilometers the comet can be observed in dark areas surprisingly
effordless with the naked
eye. But near big towns, the object is really hard to observe.
(estimated brightness 4,2 mag*).

Update: 5th
of December 2007

Left: Nikon
300mm, f4 ( 480 mm dig), Exp 90
sec, ASA 800 Canon 20D

With nearly 56 arcmin, 17P/ Holmes is nearly 2 times bigger as the moon (may 3,7 mag*).
It can be still observed in dark areas with naked
eye.

Due to the comet
measures visual 45 arcmin, the diameter must reach up to 3,7 million kilometers. 17P/Holmes is
fading surprising less (may 3,5 mag*).
No problem to see the diffuse ball in dark areas with naked
eye. The comets surrounding material in comparision to the 1,5 x
moon diameter makes it easy to discover, although the
momenty brightness is declining. Watch vertical at midnight!

The expansion of
17P/ Holmes measures now 35 arcmin, and is visual archiving more
the the moon (30,5'). Since the 5th of November the comet is the
biggest object in our solar system. The diameter reaches up to
2,5 million kilometers. 17P/Holmes is dimming (may 3,2 mag*), but
it is no problem to see the the expansiom wave with the naked
eye. By using normal binoculars it is together with the "Perseus
star" Mirfak a real magic view .

(9.Nov,0:10 UTC),
Jaufenpass (1700 müNN), Sterzing. Thank's to Martin for the
borrowing of the 600ED!

Today the expansion of
17P/ Holmes is around 21,5 arcmin, and visual archiving more
than 2/3rd of the moon (30,5'). It seems that the comet loose
it's tail. A may low solar wind isn't able to blow out the dust
from the center.

5th of November 2007

Today the expansion of
17P/ Holmes is around 17 arcmin, and visual archiving
the wide as the half of the moon (30,5'). The real diameter of 1.2 mio km
reaches now the size of our sun.*

"It" is growing and
growing! The expansion wave of the now 1.63 AU (247 Mio km)
distanced comet from the earth is measuring in its diameter around 13 arcmin! The green coma
reaches with apprx. 32 arcmin over a half degree and is a little bit bigger than the moon. Advice*: The size of the astronomy objects are in relation of
the visual figure seen from the earth. That means: 13 arcmin in
a distance of 247 million km are standing in proportion to
930.000 km! (Moon diameter only 3400 km).

After in the entire Germany and half Europe
area a sturdy
haze plate had situated itself for five days, not the smallest
cloud gap was even to be located in a radius of 300 km. After the first
attempt in Lenggries/Jachenau failed completely because of a sudden
high fog attack, the new hunt went into the weather broadcast announced mini gap
near the city of Regensburg. Of corse it was also the purest haze battle and I had to change the location
almost for
four times.

It is remarkable that the pressure wave, I
suppose it was an explosion, spreads so fast that the size of the
sky object daily increases around 1,2 arcminutes. This
would comply an expansion speed around 40.000 km per day. If the expansion
wave stays constantly in its brightness, it will may be possible to
see a small ring (my own estimation!) with the unaided eye in the night sky. Perhaps a
brighter diffuse disk up to full moon size could be observed. Let's
wait what is happening the next days /weeks.

This is
well explained by the momentaryposition sun-earth-comet (map). From the viewing point
Earth, we can see directly on the nucleus. Behind the nucleus the always sun turned away tail hides, and an asymmetrical brightness
inside the expansion wave is the reason.

*mag = > light magnitude.
Up to apprx. mag 5 stars are visible in the city with the naked eye, in very dark areas to
mag
6. --> The more high numerical value is given, the more
weak are the objects.